Lactic acid spraying on split carcasses reshapes microbial succession and reduces the occurrence of blown pack spoilage in vacuum-packaged beef stored at different temperatures over extended shelf life.

Beef is a highly perishable product due to its high moisture content, neutral pH, and rich nutrient profile, which favor microbial growth and spoilage. While vacuum packaging extends shelf life by limiting aerobic bacteria, it may promote the proliferation of anaerobic and facultative anaerobic spoilage organisms, leading to blown pack spoilage. This study investigated the effects of lactic acid spraying on split carcasses categorized by two pH levels (high or ideal) on microbial succession and volatile organic compound (VOC) production in vacuum-packaged sirloins, stored at 0 °C, 4 °C, and 7 °C for up to 120 days. Using culture-based methods, 16S rRNA gene sequencing, and VOC profiling, it has been found that lactic acid treatment significantly reduced initial bacterial loads, especially in high-pH split carcasses (P < 0,05), and modulated microbial communities over time. Treated samples exhibited a lower incidence of blown pack spoilage (BPS) under specific storage time-temperature conditions. Nevertheless, bacterial changes under specific time-temperature storage conditions were characterized by a microbiota dominated by Lactococcus, Lactobacillus, Leuconostoc, Enterococcus, Carnobacterium, Hafnia-Obesumbacterium, and Serratia, regardless type of treatment. Overall microbial diversity was not significantly affected; however, the composition of dominant bacterial genera and VOC profiles differed between treated and non-treated groups, suggesting that specific bacterial taxa and compounds may serve as indicators of spoilage progression in vacuum-packed meat under defined storage conditions.